Optical devices and systems often are used to route an optical signal therethrough, and emit the optical signal so that the emitted optical signal is directed towards a target. For example, an optical device may be used to route light supplied from an optical fiber through several optical components, such as lenses and other transparent elements, for example, transparent glass or plastic tubes, of the device, before emitting the light so the emitted light is focused at a predetermined location external to the device.
In an optical device, the optical properties of optical components through which light is passed or which reflect or refract light may determine transmission characteristics of the light emitted from the optical device. As is well known, light is composed of bundles of rays traveling in two planes, known as tangential and sagittal planes, that are orthogonal to each other. When light travels through an optical component of the optical device, the optical properties and geometry of the outer surfaces of the optical component may cause the two planes of rays of the light emitted from the optical component to have different focal lines or points, which is a condition known as astigmatism.
An optical device often includes an optical component to compensate for astigmatism expected to be caused by another optical component of the device, such that the two planes of rays constituting the light emitted from the optical device may be focused at a same focal point or line. For example, an optical probe that operates to emit light having a focus line or beam waist at a target location external to the probe sometimes includes a transparent tube through which the light is emitted from the probe. The tube of the probe acts as an optical lens that causes astigmatism in the light passing therethrough. The optical probe, therefore, includes another optical component, such as an optical prism, through which the light passes before the light passes through the tube, and which causes astigmatism in the light that compensates for the astigmatism expected to be caused by the tube. The astigmatism caused by the other optical component, thus, provides for the desirable condition that the light emitted from the optical probe has minimal or no astigmatism.
A continuing need exists for an optical component that may compensate for astigmatism caused by another optical component in an optical device and where the optical component can be manufactured with relative ease and at low cost.